34.1

Web 101.34SM – Challenges of Losing Weight/Inches

Thinking Thin?

David Roisum, Ph.D.

Finishing Technologies, Inc.

34.2

Product / Process Design Q’s

• What does the customer want/need?

• Are they willing to pay for it?

• What chemistries & materials to use?

• Can my machine make it?

34.3

Product / Process Design Q’s

• What does the customer want/need?

• Are they willing to pay for it?

• What chemistries & materials to use?

• Can my machine make it?

• Can my machine make it reliably?

34.4

Predictive Properties

• Low Strength/Stretch > Web Breaks

• Low Modulus > Width Variability

• High Modulus > Draw Control Troubles

• Laminate Differing Modulii > Curl

• Heat Addition Film > MD Wrinkles

• Moisture Addition Paper > MD Wrinkles

• Low or High Friction > Winding Troubles

34.5

Predictive Properties

• Thin Materials > Troubles

• Light Weight Materials > Troubles

34.6

Ever Lighter & Thinner

• Reduced Material Costs

• Reduced Transportation Costs

• Reduced Environmental Costs

• Better Performance

34.7

Ever Lighter & Thinner,

Are You Ready?

• Caliper & Other Profile Variations

• Wrinkling

• Air Entrainment

• Tension Control

• Roller Design

34.8

Profile Variations with Thin

• Absolute variation tends to remain same

• Relative variation tends to increaseTHICK

Caliper = 0.1Caliper Variation = 10%∆

THIN

Caliper = 0.1Caliper Variation = 20%∆

Front Back

Caliper

34.9

Profile Variation Implications

• Web Wrinkles

• Web Bagginess before & after wind

• Wound Roll Ridges

• Wound Roll Blocking

• Wound Roll Wrinkles

• Wound Roll Corrugations

34.10

Wrinkling

• The buckling (e.g. wrinkling) resistance of

a web goes with the cube of caliper.

8W1W

T= 2 T= 1

34.11

Wrinkling Implications

Higher waste rates unless:

• Web width is reduced or,

• More frequent and effective Spreading

• Fewer rollers

• Better roller tolerances

34.12

Air Entrainment

• Entrained air is inversely proportional to

tension (e.g. caliper)

Roller RollH H

Air Air

34.13

Air Entrainment Implications

Roller

• Loss of traction

• Loss of tension

control

• Loss of path control

• Web scratching

Roll

• Loose Winding

• Out-of-round

• Telescoping

• Buckles

34.14

Air Entrainment Treatments

Roller

• Decrease Speed

• Increase Tension

• Grooving

• Texturizing

• Vacuum

Roll

• Decrease Speed

• Increase Tension

• Layon Roller Nip

• Center/Surface Wind

34.15

Tension Setpoint

• Tension Setpoint is determined by the Web

• Nominal tension is reduced with caliper

• 0.25-1.0 PLI per mil of thicknes

• 10-25% of MD web Tensile Strength

34.16

Tension Control Quality

• Tension Variability is determined by the

Machine

• Sensors: dancers and load cells

• Active elements: brakes, motors

• Passive elements: rollers

34.17

Tension Control Sensors

Avoid ‘Weighing a Pea in a Dumptruck’

• Dancer friction << 10% of min tension

• Load cell resolution << 10% of min tension

34.18

Tension Control Actuators

Avoid ‘Using a V-8 Engine to Run a Pencil

Sharpener’

• Brake/Dancer pressure > 10 PSI

• Motor amps > 10% of rated maximum

continuous duty

34.19

Roller Bearing Friction

• Parasitic tension is a function of the

number of rollers and bearing drag

• Bearing diameter, seals & lubrication

• Causes tension to rise within a drive

section.

Position

Tension

34.20

Roller Inertia

• Inertial tension upset is a function of the

number of rollers and roller inertia

• Diameter, wall thickness, material

• Causes tension to vary within a drive

section.

Position

Accel

Decel

Run

Tension

34.21

Roller Geometrical Quality

To Avoid Wrinkling:

• Diametral Tolerance

• Alignment Tolerance

34.22

Thin Checklist

• Desirable tension

• Caliper Quality

• Wrinkle Waste

• Air Entrain vs Speed

• Tension Actuator Size

• Tension Sensor Size

• Roller Count

• Roller Drag

• Roller Inertia

• Roller Diametral Std

• Roller Alignment Std

• Roller Surface Texture

34.23

Summary:

• Don’t let the excitement of a new product

blind you to real risks.

• Prepare for thin.

• Thin can be trouble

34.24

Review Questions

• What is DFM mean?

• What types of waste can be expected to

increase with thinner materials?

• What are some machine design challenges

for thin materials?

34.25

Review Answers

• What is DFM mean?

– Design For Manufacturability. Design the web product (thick enough) so that it can be run reliably on your machine.

• What types of waste can be expected to increase with thinner materials?

– Wrinkling, winding

• What are some machine design challenges for thin materials?

– Light tension control, roller geometry

26

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